Are you asking how you might go from a gene name to an ensembl gene ID? Would biomart be any help, e.g. http://www.biomart.org/biomart/martview or the perl api?
on the "filters" section go to the "gene" subsection the list of geneIDs of interest ("HGNC symbols" would be the selection for what is commonly understood by known gene name)
on the "attributes" section select the "sequences" radio button, go to the "sequences" subsection and choose "exon sequences"
this will give you the information you need, but of course you may play around with all the options available if you want to obtain more information from this great database interface.
unfortunately not. if you dig into the BRCA2 gene you will find 6 transcripts, being that ENST00000533776 the 6th, a retained intron which is described as "no protein product". having in mind that my biological background is limited, my guess would be that maybe if you select "coding sequences" strictly they won't be able to provide you with the sequence of an intron. hope this helps.
Are you asking how you might go from a gene name to an ensembl gene ID? Would biomart be any help, e.g. http://www.biomart.org/biomart/martview or the perl api?